I don’t think you will find much support for making people pay to create a gig. There are other freelancing sites that charge you for selling and one of Fiverr’s unique points is that it doesn’t. I don’t see how new sellers cause problems for leveled selelrs. If their gigs are bad, they won’t sell and eventually the person will leave. If their gigs are good and they do well, they will bring more traffic to the site for everyone.
Good gigs do increase competition on the site, but that wouldn’t stop because of a small fee. Competition still doesn’t hurt you, though. If you have great gigs, are honest and have something unique to offer you will do well even when other people are creating gigs. That’s only my own opinion, however.